The Polycomb (PcG) superfamily of genes includes repressors of gene expression. PcG proteins form large, multimeric, chromatin-associated protein complexes that regulate genes, such as the homeotic genes involved in axial patterning, limb formation and other aspects of development. They may also be important in regulating cell growth and differentiation through regulation of the cell cycle, and have accordingly been targeted for use as therapeutic, prognostic, and diagnostic tools for proliferative and developmental disorders. There is accordingly a need for the identification of new genes in this family.